This invention relates generally to the field of gas-liquid transfer and more particularly to a method of and means for adding gas such as air to a tank or other body of subsaturated liquid.
While the invention may be advantageously utilized in a variety of gas-liquid transfer applications including, for example, the addition of chlorine into water in water treatment plants and the addition of chlorine into pulp stock in the papermaking art, the invention finds particular utility in the field of reaeration of oxygen deficient or undersaturated liquid.
For example, in the activated sludge process of sewage treatment the incoming sewage, after passing through a presettling tank from which raw sludge is removed, is directed into an aeration tank for the purpose of adding oxygen to the liquid. This process, generally known as aeration, is generally accomplished in the aeration tank by means of compressed air which is diffused into the liquid by various devices, including filter plates, filter tubes and ejectors, or by means of mechanical agitators.
While the term "aeration" is commonly used in connection with processes for treating waste material, it is used herein, in addition to the foregoing, in connection with any process or system by which gas is transferred into subsaturated liquid. Jet aeration is defined herein as an aeration system which utilizes apparatus for directing a stream or jet of gas-liquid mixture into a tank or other body of the liquid to increase the gas content thereof.
While known systems of jet aeration are advantageously employed in a variety of applications, the present invention represents improvements in jet aeration and in aerators used in jet aeration systems which reduce operating costs, increase efficiencies, minimize maintenance down time and reduce fabrication and installation costs.